statistics: do not directly update global stats when dropping a parti…

…tion (#48846)

ref #48182

pkg/statistics/handle/ddl/ddl.go

@@ -116,16 +116,8 @@ func (h *ddlHandlerImpl) HandleDDLEvent(t *util.DDLEvent) error {
  }
  }
  case model.ActionDropTablePartition:
- pruneMode, err := util.GetCurrentPruneMode(h.statsHandler.SPool())
- if err != nil {
- return err
- }
- globalTableInfo, droppedPartitionInfo := t.GetDropPartitionInfo()
- if variable.PartitionPruneMode(pruneMode) == variable.Dynamic && droppedPartitionInfo != nil {
- if err := h.globalStatsHandler.UpdateGlobalStats(globalTableInfo); err != nil {
- return err
- }
- }
+ // TODO: Update the modify count and count for the global table.
+ _, droppedPartitionInfo := t.GetDropPartitionInfo()
  for _, def := range droppedPartitionInfo.Definitions {
  if err := h.statsWriter.ResetTableStats2KVForDrop(def.ID); err != nil {
  return err

pkg/statistics/handle/globalstats/BUILD.bazel

@@ -16,7 +16,6 @@ go_library(
  "//pkg/parser/model",
  "//pkg/sessionctx",
  "//pkg/sessionctx/stmtctx",
- "//pkg/sessiontxn",
  "//pkg/statistics",
  "//pkg/statistics/handle/logutil",
  "//pkg/statistics/handle/storage",

pkg/statistics/handle/globalstats/global_stats.go

@@ -22,10 +22,8 @@ import (
  "github.com/pingcap/tidb/pkg/parser/ast"
  "github.com/pingcap/tidb/pkg/parser/model"
  "github.com/pingcap/tidb/pkg/sessionctx"
- "github.com/pingcap/tidb/pkg/sessiontxn"
  "github.com/pingcap/tidb/pkg/statistics"
  statstypes "github.com/pingcap/tidb/pkg/statistics/handle/types"
- "github.com/pingcap/tidb/pkg/statistics/handle/util"
  "github.com/pingcap/tidb/pkg/types"
  "github.com/pingcap/tidb/pkg/util/logutil"
  "github.com/tiancaiamao/gp"
@@ -57,14 +55,6 @@ func (sg *statsGlobalImpl) MergePartitionStats2GlobalStatsByTableID(sc sessionct
  return MergePartitionStats2GlobalStatsByTableID(sc, sg.statsHandler, opts, is, physicalID, isIndex, histIDs)
 }
 
-// UpdateGlobalStats will trigger the merge of global-stats when we drop table partition
-func (sg *statsGlobalImpl) UpdateGlobalStats(tblInfo *model.TableInfo) error {
- // We need to merge the partition-level stats to global-stats when we drop table partition in dynamic mode.
- return util.CallWithSCtx(sg.statsHandler.SPool(), func(sctx sessionctx.Context) error {
- return UpdateGlobalStats(sctx, sg.statsHandler, tblInfo)
- })
-}
-
 // GlobalStats is used to store the statistics contained in the global-level stats
 // which is generated by the merge of partition-level stats.
 // It will both store the column stats and index stats.
@@ -170,107 +160,6 @@ var analyzeOptionDefault = map[ast.AnalyzeOptionType]uint64{
  ast.AnalyzeOptNumTopN: 20,
 }
 
-// UpdateGlobalStats update the global-level stats based on the partition-level stats.
-func UpdateGlobalStats(
- sctx sessionctx.Context,
- statsHandle statstypes.StatsHandle,
- tblInfo *model.TableInfo) error {
- tableID := tblInfo.ID
- is := sessiontxn.GetTxnManager(sctx).GetTxnInfoSchema()
- globalStats, err := statsHandle.TableStatsFromStorage(tblInfo, tableID, true, 0)
- if err != nil {
- return err
- }
- // If we do not currently have global-stats, no new global-stats will be generated.
- if globalStats == nil {
- return nil
- }
- opts := make(map[ast.AnalyzeOptionType]uint64, len(analyzeOptionDefault))
- for key, val := range analyzeOptionDefault {
- opts[key] = val
- }
- // Use current global-stats related information to construct the opts for `MergePartitionStats2GlobalStats` function.
- globalColStatsTopNNum, globalColStatsBucketNum := 0, 0
- for colID := range globalStats.Columns {
- globalColStatsTopN := globalStats.Columns[colID].TopN
- if globalColStatsTopN != nil && len(globalColStatsTopN.TopN) > globalColStatsTopNNum {
- globalColStatsTopNNum = len(globalColStatsTopN.TopN)
- }
- globalColStats := globalStats.Columns[colID]
- if globalColStats != nil && len(globalColStats.Buckets) > globalColStatsBucketNum {
- globalColStatsBucketNum = len(globalColStats.Buckets)
- }
- }
- if globalColStatsTopNNum != 0 {
- opts[ast.AnalyzeOptNumTopN] = uint64(globalColStatsTopNNum)
- }
- if globalColStatsBucketNum != 0 {
- opts[ast.AnalyzeOptNumBuckets] = uint64(globalColStatsBucketNum)
- }
- // Generate the new column global-stats
- newColGlobalStats, err := MergePartitionStats2GlobalStats(sctx, statsHandle, opts, is, tblInfo, false, nil)
- if err != nil {
- return err
- }
- if len(newColGlobalStats.MissingPartitionStats) > 0 {
- logutil.BgLogger().Warn("missing partition stats when merging global stats", zap.String("table", tblInfo.Name.L),
- zap.String("item", "columns"), zap.Strings("missing", newColGlobalStats.MissingPartitionStats))
- }
- for i := 0; i < newColGlobalStats.Num; i++ {
- hg, cms, topN := newColGlobalStats.Hg[i], newColGlobalStats.Cms[i], newColGlobalStats.TopN[i]
- if hg == nil {
- // All partitions have no stats so global stats are not created.
- continue
- }
- // fms for global stats doesn't need to dump to kv.
- err = statsHandle.SaveStatsToStorage(tableID, newColGlobalStats.Count, newColGlobalStats.ModifyCount,
- 0, hg, cms, topN, 2, 1, false, util.StatsMetaHistorySourceSchemaChange)
- if err != nil {
- return err
- }
- }
-
- // Generate the new index global-stats
- globalIdxStatsTopNNum, globalIdxStatsBucketNum := 0, 0
- for _, idx := range tblInfo.Indices {
- globalIdxStatsTopN := globalStats.Indices[idx.ID].TopN
- if globalIdxStatsTopN != nil && len(globalIdxStatsTopN.TopN) > globalIdxStatsTopNNum {
- globalIdxStatsTopNNum = len(globalIdxStatsTopN.TopN)
- }
- globalIdxStats := globalStats.Indices[idx.ID]
- if globalIdxStats != nil && len(globalIdxStats.Buckets) > globalIdxStatsBucketNum {
- globalIdxStatsBucketNum = len(globalIdxStats.Buckets)
- }
- if globalIdxStatsTopNNum != 0 {
- opts[ast.AnalyzeOptNumTopN] = uint64(globalIdxStatsTopNNum)
- }
- if globalIdxStatsBucketNum != 0 {
- opts[ast.AnalyzeOptNumBuckets] = uint64(globalIdxStatsBucketNum)
- }
- newIndexGlobalStats, err := MergePartitionStats2GlobalStats(sctx, statsHandle, opts, is, tblInfo, true, []int64{idx.ID})
- if err != nil {
- return err
- }
- if len(newIndexGlobalStats.MissingPartitionStats) > 0 {
- logutil.BgLogger().Warn("missing partition stats when merging global stats", zap.String("table", tblInfo.Name.L),
- zap.String("item", "index "+idx.Name.L), zap.Strings("missing", newIndexGlobalStats.MissingPartitionStats))
- }
- for i := 0; i < newIndexGlobalStats.Num; i++ {
- hg, cms, topN := newIndexGlobalStats.Hg[i], newIndexGlobalStats.Cms[i], newIndexGlobalStats.TopN[i]
- if hg == nil {
- // All partitions have no stats so global stats are not created.
- continue
- }
- // fms for global stats doesn't need to dump to kv.
- err = statsHandle.SaveStatsToStorage(tableID, newIndexGlobalStats.Count, newIndexGlobalStats.ModifyCount, 1, hg, cms, topN, 2, 1, false, util.StatsMetaHistorySourceSchemaChange)
- if err != nil {
- return err
- }
- }
- }
- return nil
-}
-
 // blockingMergePartitionStats2GlobalStats merge the partition-level stats to global-level stats based on the tableInfo.
 // It is the old algorithm to merge partition-level stats to global-level stats. It will happen the OOM. because it will load all the partition-level stats into memory.
 func blockingMergePartitionStats2GlobalStats(

pkg/statistics/handle/globalstats/globalstats_test.go

@@ -903,32 +903,22 @@ func TestDDLPartition4GlobalStats(t *testing.T) {
  globalStats := h.GetTableStats(tableInfo)
  require.Equal(t, int64(15), globalStats.RealtimeCount)
 
- tk.MustExec("alter table t drop partition p3, p5;")
- require.NoError(t, h.DumpStatsDeltaToKV(true))
- require.NoError(t, h.HandleDDLEvent(<-h.DDLEventCh()))
- require.NoError(t, h.Update(is))
- result = tk.MustQuery("show stats_meta where table_name = 't';").Rows()
- require.Len(t, result, 5)
- // The value of global.count will be updated automatically after we drop the table partition.
- globalStats = h.GetTableStats(tableInfo)
- require.Equal(t, int64(11), globalStats.RealtimeCount)
-
  tk.MustExec("alter table t truncate partition p2, p4;")
  require.NoError(t, h.DumpStatsDeltaToKV(true))
  require.NoError(t, h.HandleDDLEvent(<-h.DDLEventCh()))
  require.NoError(t, h.Update(is))
  // The value of global.count will not be updated automatically when we truncate the table partition.
  // Because the partition-stats in the partition table which have been truncated has not been updated.
  globalStats = h.GetTableStats(tableInfo)
- require.Equal(t, int64(11), globalStats.RealtimeCount)
+ require.Equal(t, int64(15), globalStats.RealtimeCount)
 
  tk.MustExec("analyze table t;")
  result = tk.MustQuery("show stats_meta where table_name = 't';").Rows()
  // The truncate operation only delete the data from the partition p2 and p4. It will not delete the partition-stats.
- require.Len(t, result, 5)
+ require.Len(t, result, 7)
  // The result for the globalStats.count will be right now
  globalStats = h.GetTableStats(tableInfo)
- require.Equal(t, int64(7), globalStats.RealtimeCount)
+ require.Equal(t, int64(11), globalStats.RealtimeCount)
 }
 
 func TestGlobalStatsNDV(t *testing.T) {

pkg/statistics/handle/types/interfaces.go

@@ -348,9 +348,6 @@ type StatsGlobal interface {
  isIndex bool,
  histIDs []int64,
  ) (globalStats interface{}, err error)
-
- // UpdateGlobalStats will trigger the merge of global-stats when we drop table partition
- UpdateGlobalStats(tblInfo *model.TableInfo) error
 }
 
 // DDL is used to handle ddl events.